Questions tagged [data-flow-analysis]
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37 questions
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$IN[BB]=\emptyset$ for all $BB$ instead of $IN[BB]=U,\text{for all other BB != BB_EXIT}$ in Init of Anticipated Expression Dataflow analysis in SSA
I am implementing an LLVM pass for anticipated expressions using dataflow analysis and code hoisting. The reference I am following is the Purple Dragon Book (Compilers: Principles, Techniques, and ...
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How to verify no side effects from added code in C++?
I am currently working on a C++ project where I've introduced some new code to extend its functionality. However, it is very important to ensure that this new code does not introduce any side effects ...
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Basic Blocks: Interrupted by "pointless" goto?
So I was studying some about compiler optimizations and as part of that, Control Flow Graphs (CFG's).
Specifically, I saw a "basic block" being defined as "a straight-line code sequence ...
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data flow analysis reaching definition analysis meaning
I'm trying to understand reaching definitions and I'm having hard problem wrapping it around my head with the following definition (taken from the the following paper page 114):
$B_i\;\text{be a ...
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Dataflow Analysis: Available Expressions, why is OUT[B] initialized to universal set?
In the dragon book, section 9.2.6, why is the $OUT[B]$ initialized to $U$ except for $OUT[ENTRY]$. Wouldn't using the $OUT[B] = \emptyset \quad \forall B$ be a more conservative solution? The book ...
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What is the intepretation of the top & bottom elements of a lattice?
(moved from stackoverflow to here)
I'm trying to understand dataflow stuff for program analysis. Transfer functions move lattice elements up (towards top ⊤) and down (towards bottom ⊥). Sometimes the ...
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Is there a functional programming language with inherent change propagation?
Change propagation in programming environments is an add-on at the framework level such as React.
There was a lot of work on dataflow virtual machines in the wake of Backus's Turing Award Lecture on ...
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Can reading a value of a variable kill the definition of the variable?
I was going through the concept of reaching definitions from the red dragon book.
The authors define reaching definitions as follows:
Definition: We say a definition $d$ reaches a point $p$ if there ...
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How do we know that $F^{n + 1}(\overrightarrow{\emptyset}) = F(F^n(\overrightarrow{\emptyset}))$?
I am currently studying the textbook Principles of Program Analysis by Flemming Nielson, Hanne R. Nielson, and Chris Hankin. Chapter 1.3 Data Flow Analysis says the following:
The least solution. The ...
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Showing that $F$ is a monotone function
I am currently studying the textbook Principles of Program Analysis by Flemming Nielson, Hanne R. Nielson, and Chris Hankin. Chapter 1.3 Data Flow Analysis says the following:
The least solution. The ...
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Which language is used to construct a type system?
Typically, OCaml and Scala seem to be used for designing any programming languages tool. But what features offer them an edge over other languages.
A related question, is a type system for a language ...
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Difference between forward/backward slicing and reaching definition - def/use - use/def chains
I'm a little bit confused about the difference between forward/backward slicing and the use/def-def/use as part of the reaching definitions technique. Isn't the use-def chain supposed to be equivalent ...
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Difference between data flow and control flow
I am trying to read a paper. I can’t understand the difference between data flow and control. Maybe control flow means OS's or hardware's steps taken for execution of statements whereas data flow ...
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Compiler design: How are the initialize conditions for data-flow problems set?
Consider a typical data-flow problem, for example, reaching definitions or available expressions.
I am struggling to understand how $IN$ and $OUT$ of the basic blocks are initialized. For example, ...
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How to draw flowchart for if condition within nested loops?
Please find my program logic as below :
Please find my flowchart for the above program logic as below:
My superior asked me correct the flowchart. But I couldn't identify my mistakes.
Please guide me ...
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